Big Clouds of White Smoke
 

Hi guys. I have a 1990 Supra 7MGE manual trans. Over the past two weeks I have been running into some problems. I had a heater hose spring a leak on me, which I mistook for the water pump due to its location, resealed the water pump, found and replaced the leaking hose, and have developed a very strange problem. When I start the car up, and drive around, as soon as I get to full operating temperature, the car starts to miss and blows out big cloads of white smoke for a few seconds until the engine gets up to speed and clears out and starts operating normally without the miss. It only occurs at operating temp. I have been checking the smell of the smoke and exhaust and am fairly certain that it is NOT coolant, but is fuel. It smells chemically rather than that sweet smell(which I have smelled when I have BHG).

So quick explanation of what i have been doing to try to stop this:
-Replaced distributor cap and rotor
-replaced spark plugs and wires
-replaced air filter with k&n drop in
-resealed water pump

So I am kinda at my wit's end right now. I have tried so many things to get it to stop, including disconnecting the cold start injector (thinking that maybe it was dumping fuel into the system when it shouldn't be). The only thing I have left idea-wise is perhaps my battery isn't putting enough juice through the system.The battery has been weak for a while now(i have tested it several times recently and it has passed with a simple "charge required"), but the smoking is brand new. Any ideas would be massively appreciated. Thanks.

EDIT: Forgot to add, I am not experiencing any of the normal symptoms I have had with BHG. No power loss, no over pressuring of the cooling system(altho I have a slight leak at the heater core), no over heating, etc.

Not all coolant smells sweet when heated.... the more common ones do though (primarily the green stuff).

Could you be more descriptive of the smell? Does it smell like sulphur? You may be experiencing multiple issues and a BHG isn't out of the question. I'd start with testing the coolant pH and a compression test.

My money's on a BHG. It's a 7M afterall, I've got a 8 out of 10 chance of being right... easy money. :naughty:

True, BHG is still on the table. The smell is almost like the smell of brake cleaner with a hint of fuel. This makes sense since it is missing so badly. I am still really curious about the possibility of the battery not giving enough juice. I'm going to try to do a compression test tomorrow afternoon. I'll come back with the results once it is done.

Realistically, BHG is most likely, but all the signs seem inconsistent. It is completely different to 3 occasions of BHG i have had.

A weak battery isn't going to affect how the engine runs very much unless there's something significantly wrong with it. The alternator is what you need to look at if you think that's the issue.

BHG's can cause many different symptoms depending on where it's blown and how big the leaks are.

Did you read the old spark plugs before disposing of them? If not, do you still have them? If the problem is in or before the combustion chamber they'll give you a very good idea what problems you may be facing and in which cylinders.

Battery is definitely a problem, but a separate one. Did the compression test and was getting about 145-150 PSI in cylinders 1-4, but neither cylinder 5 or 6 would get over 130. Unfortunately, I think you bet on the right horse. It's looking more and more like a BHG. Gotta start figuring out when I can do the work since this is my daily driver.

Look down through the spark plug holes at the crown of each piston. If 5 and 6 look much cleaner then you're probably losing coolant into those cylinders. This could also cause an incomplete burn adding unspent fuel to the mix coming out of the exhaust (hence the atypical odor). Have you not been losing any coolant?

I have been losing a little bit of coolant, not too fast, but I assumed it was due to a small leak, as I almost always have a tiny drip... I was getting a fiz as i refilled the coolant after opening up the thermostat housing which was like the nail in the coffin for me. Ordered the head gasket kit, and will hopefully have it tmw. The exhaust has started to develop a slight sweet smell... I just find it strange how I'm getting the BHG with all completely different symptoms from the last couple of times it has happened. Sadly, the smoking is getting worse, so I had to jump on this before it causes a much worse problem.

EDIT: Does anyone know a good place to order the molded heater hoses for the 7M engine? I hate ordering from toyota cuz it always takes forever to get the parts i need now...